Sometimes Google makes logical investments, like when it bought YouTube, or Android.

Other times though, Google's decisions leave us scratching our heads.

Some examples of weird uses of cash (click on each item to learn more): Windmills, beekeepers, and space travel.

Remember: Google is a web-based advertising and software company. Why does it blow money on things like spacetrips and bicycle-powered monorails? These are obviously non-core businesses and investments.

Our guess: Funding quirky projects like windmills and beekeeping is Google's way of defining its brand. These projects also boost employee morale, and remind employees they can still change the world working at Google.

That's fine and good, but if shareholders get another year so of flat stock due to a decelerating single revenue stream, they might start wondering why the company's money doesn't entirely go toward reinvestment closer to Google's core competencies.

Google blew $40 million on Windmills

Google really likes to spend money on clean energy projects. But $40 million on Windmills? This has nothing to do with Google's core business. Why burn the money?

Google creating an $86 million low-income housing tax credit

Courtesy of Journal of Tax Credits

At the end of last August, Google announced it was creating an $86 million low income tax credit fund with US Bancorp. In a press release announcing the news Google VP/treasurer Brent Callinicos said, “In recent years there has been a void in affordable housing investment. Our investment with USBCDC allows us to further our goal of providing relief to people who otherwise may not have access to quality housing.”

Google will be able to offset federal tax liabilities for years thanks to this one, says TechCrunch.

Playing the Energy Market

Associated Press

Google is selling energy on the spot market thanks to a deal where it bought 114 megawatts of Wind power from NextEra Energy. It's a very unusual move to say the least. The power would be enough to power several data centers, but Google doesn't have data centers near the Iowa windfarm it bought the energy from. So, Google is just speculating.

Beekeeper

Mercury News

In fairness to Google, this one isn't that weird and it's not that expensive. Google has an official beekeeper. He takes care of 4 bee's nests on Google's campus. The chef at Google thought it would be a good idea to have bees nearby for fresh honey.

Invested $1 million in shweeb, a human powered monorail

This one is just crazy. Shweeb puts people in clear pods which are powered by people kicking their legs as if on a bicycle. Google gave the company $1 million to see if it can make the Shweeb an eco-friendly transportation company.

Google fiber optics for a super fast internet

via Trends Updates

Google is building a super fast fiber Internet network in Kansas City. Why? Well a Google rep once tried to explain to us that it's good for Google if more people use high speed Internet. Okay, we guess. But why is Google doing this?

Investment in Clearwire

Google invested $500 million in Clearwire a few years back. At the time, Google said Clearwire would, "provide wireless consumers with real choices for the software applications, content and handsets that they desire." And that's why it was investing. Clearly, it changed its mind about Clearwire at some point because it hasn't put anymore money in. And we're not sure how the investment helps Google now.

Prototype mirror for solar

Google is very into the clean energy market. To that end it's investing in building a prototype of a solar panel that could reduce the cost of solar energy by 2X. Neat. But again, why is GOOGLE doing this? (We're being a bit facetious, of course. We know why -- Larry Page believes in dreaming big, and trying to change the world. But why not spin out the solar project?)

$3.9 million in 23andMe

Robert Scoble via Flickr

The decision to invest $3.9 million in 23andMe, the startup founded by Sergey Brin's wife was controversial. 23andMe immediately used the money to pay back Sergey who had loaned $2.6 million out of his own pocket. This has nothing to do with Google's core business, and it sure looks bad, so why do it?

The $30 million Google Lunar X Prize

via Tech Shout

Google is dangling $30 million out there for the first privately funded team to "to send a robot to the moon, travel 500 meters and transmit video, images and data back to the Earth."